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  • Open Access

    ARTICLE

    Dimensional Amplitude Response Analysis of Vibrations Produced by Defects in Rolling Contact Bearings

    Imran M. Jamadar1,*, B. Suresha1, Prasanta Kumar Samal1, S. A. I. Bellary2

    Sound & Vibration, Vol.56, No.2, pp. 165-191, 2022, DOI:10.32604/sv.2022.015267

    Abstract Usage of rolling contact bearings in variety of rotor-dynamic applications has put forth a need to develop a detailed and easy to implement techniques for the assessment of damage related features in these bearings so that before mechanical failure, maintenance actions can be planned well in advance. In accordance to this, a method based on dimensional amplitude response analysis and scaling laws is presented in this paper for the diagnosis of defects in different components of rolling contact bearings in a dimensionally scaled rotor-bearing system. Rotor, bearing, operating and defect parameters involved are detailed for dimensional analysis using frequency domain… More >

  • Open Access

    ARTICLE

    Hybrid Metamodeling/Metaheuristic Assisted Multi-Transmitters Placement Planning

    Amir Parnianifard1, Muhammad Saadi2, Manus Pengnoo1, Muhammad Ali Imran3, Sattam Al Otaibi4, Pruk Sasithong1, Pisit Vanichchanunt5, Tuchsanai Polysuwan6, Lunchakorn Wuttisittikulkij1,*

    CMC-Computers, Materials & Continua, Vol.68, No.1, pp. 569-587, 2021, DOI:10.32604/cmc.2021.015730

    Abstract With every passing day, the demand for data traffic is increasing, and this urges the research community not only to look for an alternating spectrum for communication but also urges radio frequency planners to use the existing spectrum efficiently. Cell sizes are shrinking with every upcoming communication generation, which makes base station placement planning even more complex and cumbersome. In order to make the next-generation cost-effective, it is important to design a network in such a way that it utilizes the minimum number of base stations while ensuring seamless coverage and quality of service. This paper aims at the development… More >

  • Open Access

    ARTICLE

    Hybrid Metamodel—NSGA-III—EDAS Based Optimal Design of Thin Film Coatings

    Kamlendra Vikram1, Uvaraja Ragavendran2, Kanak Kalita1,*, Ranjan Kumar Ghadai3, Xiao-Zhi Gao4

    CMC-Computers, Materials & Continua, Vol.66, No.2, pp. 1771-1784, 2021, DOI:10.32604/cmc.2020.013946

    Abstract In this work, diamond-like carbon (DLC) thin film coatings are deposited on silicon substrates by using plasma-enhanced chemical vapour deposition (PECVD) technique. By varying the hydrogen (H2) flow rate, CH4−Argon (Ar) flow rate and deposition temperature (Td) as per a Box-Behnken experimental design (BBD), 15 DLC deposition experiments are carried out. The Young’s modulus (E) and the coefficient of friction (COF) for the DLCs are measured. By using a second-order polynomial regression approach, two metamodels are built for E and COF, that establish them as functions of H2 flow rate, CH4-Ar flow rate and Td. A non-dominated sorting genetic algorithm… More >

  • Open Access

    ARTICLE

    Robust Design Optimization and Improvement by Metamodel

    Shufang Song*, Lu Wang, Yuhua Yan

    CMES-Computer Modeling in Engineering & Sciences, Vol.125, No.1, pp. 383-399, 2020, DOI:10.32604/cmes.2020.09588

    Abstract The robust design optimization (RDO) is an effective method to improve product performance with uncertainty factors. The robust optimal solution should be not only satisfied the probabilistic constraints but also less sensitive to the variation of design variables. There are some important issues in RDO, such as how to judge robustness, deal with multi-objective problem and black-box situation. In this paper, two criteria are proposed to judge the deterministic optimal solution whether satisfies robustness requirment. The robustness measure based on maximum entropy is proposed. Weighted sum method is improved to deal with the objective function, and the basic framework of… More >

  • Open Access

    ARTICLE

    Electromechanical Admittance -- Based Damage Identification Using Box-Behnken Design of Experiments

    C.P. Providakis1, M.E. Voutetaki

    Structural Durability & Health Monitoring, Vol.3, No.4, pp. 211-228, 2007, DOI:10.3970/sdhm.2007.003.211

    Abstract Piezoceramic transducers have emerged as new tools for the health monitoring of large-scale structures due to their advantages of active sensing, low cost, quick response, availability in different shapes, and simplicity for implementations. In the present paper, a statistical metamodeling utilization of electro-mechanical (E/M) admittance approach by applying piezoelectric materials to the damage identification is investigated. A response surface metamodel is constructed by empirically fitting a model to a set of design points chosen using a Box-Behnken design of experiment (simulation) technique. This empirical fit allows polynomial models to be produced for relating damage parameter such that stiffness reduction to… More >

  • Open Access

    ARTICLE

    A Robust Inverse Method Based on Least Square Support Vector Regression for Johnson-cook Material Parameters

    Hu Wang1, Weiyi Li1, Guangyao Li1

    CMC-Computers, Materials & Continua, Vol.28, No.2, pp. 121-146, 2012, DOI:10.3970/cmc.2012.028.121

    Abstract The purpose of this study is to propose a robust inverse method for estimating Johnson-Cook material parameters. The method is shown through illustrative examples for two different advanced high strength steel (AHSS) materials (DP980 and TRIP780) using set of data from impact experiments with different velocities. Compared with widely mixed numerical experimental methods, the suggested inverse method has the capability to guarantee the robustness of the obtained parameters by considering uncertainties. The inverse problem is converted into multi-objective optimization problems. Furthermore, in order to improve the performance in efficiency and accuracy, metamodeling techniques and global optimization method are integrated. The… More >

  • Open Access

    ARTICLE

    A Metamodel-Based Global Algorithm for Mixed-Integer Nonlinear Optimization and the Application in Fuel Cell Vehicle Design

    Haoxiang Jie1,2, Huihong Shi3, Jianwan Ding2,4, Yizhong Wu2, Qian Yin2

    CMES-Computer Modeling in Engineering & Sciences, Vol.108, No.3, pp. 193-214, 2015, DOI:10.3970/cmes.2015.108.193

    Abstract This paper improves the adaptive metamodel-based global algorithm (AMGO), which is presented for unconstrained continuous problems, to solve mixed-integer nonlinear optimization involving black-box and expensive functions. The new proposed method is called as METADIR, which can be divided into two stages. In the first stage, the METADIR adopts extended DIRECT method to constantly subdivide the design space and identify the sub-region that may contain the optimal value. When iterative points gather into a sub-region to some extent, we terminate the search progress of DIRECT and turn to the next stage. In the second phase, a local metamodel is constructed in… More >

  • Open Access

    ARTICLE

    Differing Mapping using Ensemble of Metamodels for Global Variable-fidelity Metamodeling

    Qi Zhou1, Xinyu Shao1, Ping Jiang1,2, Longchao Cao1, Hui Zhou1, Leshi Shu1

    CMES-Computer Modeling in Engineering & Sciences, Vol.106, No.5, pp. 323-355, 2015, DOI:10.3970/cmes.2015.106.323

    Abstract Computational simulation models with different fidelity have been widely used in complex systems design. However, running the most accurate simulation models tends to be very time-consuming and can therefore only be used sporadically, while incorporating less accurate, inexpensive models into the design process may result in inaccurate design alternatives. To make a trade-off between high accuracy and low expense, variable fidelity (VF) metamodeling approaches that aim to integrate information from both low fidelity (LF) and high-fidelity (HF) models have gained increasing popularity. In this paper, a Difference Mapping Framework using Ensemble of Metamodels (DMF-EM) for global VF metamodeling is proposed.… More >

  • Open Access

    ARTICLE

    Sequential Approximate Optimization Procedure based on Sample-reusable Moving Least Squares Meta-model and its Application to Design Optimizations

    Jin Yeon Cho1, Min Hwan Oh1

    CMES-Computer Modeling in Engineering & Sciences, Vol.66, No.3, pp. 187-214, 2010, DOI:10.3970/cmes.2010.066.187

    Abstract In this work, a sample-reusable sequential approximate optimization (SAO) procedure is suggested. The suggested sequential approximate optimization procedure utilizes a newly proposed sample-reusable meta-model along with the trust region algorithm. Domain of design is sequentially updated to search for the optimal solution through the trust region algorithm, and the system response in the updated design region at each sequential stage is approximated by the proposed sample-reusable meta-model. The proposed sample-reusable meta-model is based on the moving least squares(MLS) approximation scheme. Thanks to the merits of moving least squares scheme, the proposed meta-model can fully utilize the previously sampled responses as… More >

  • Open Access

    ARTICLE

    Genetic Programming Metamodel for Rotating Beams

    Anuj Pratap Singh, V. Mani, Ranjan Ganguli1

    CMES-Computer Modeling in Engineering & Sciences, Vol.21, No.2, pp. 133-148, 2007, DOI:10.3970/cmes.2007.021.133

    Abstract This paper investigates the use of Genetic Programming (GP) to create an approximate model for the non-linear relationship between flexural stiffness, length, mass per unit length and rotation speed associated with rotating beams and their natural frequencies. GP, a relatively new form of artificial intelligence, is derived from the Darwinian concept of evolution and genetics and it creates computer programs to solve problems by manipulating their tree structures. GP predicts the size and structural complexity of the empirical model by minimizing the mean square error at the specified points of input-output relationship dataset. This dataset is generated using a finite… More >

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